JPH0764254B2 - Hydraulic control device for anti-skidding - Google Patents

Description

TECHNICAL FIELD The present invention relates to an antiskid hydraulic pressure control device used in a brake device of a vehicle or the like.

[Conventional technology]

The applicant has previously proposed, as an apparatus of this type, a cut valve arranged between a master cylinder and a wheel cylinder, and a volume chamber formed on the wheel cylinder side of the cut valve,
A control piston that is movably provided to open and close the cut valve and that can increase or decrease the volume of the volume chamber, and the control piston that is formed on the opposite side of the control piston from the volume chamber A pressure chamber into which a pressure that urges the cut valve in the direction of opening the cut valve is introduced, and a loading command from a control unit that is provided to be able to supply the discharge pressure to the pressure chamber and that determines the rotation state of the wheels. An electromagnetic pump driven based on the control unit and an electromagnetic valve that switches from a cutoff position to a communication position based on a loosening command from the control unit and connects the pressure chamber to the suction side of the electromagnetic pump are provided. .

In such a case, in order to normally connect the two so that pressure can be supplied from the master cylinder to the wheel cylinders,
The pressure inside the pressure chamber, which is shut off from the suction side of the electromagnetic pump with the solenoid valve in the shutoff position, is kept at a predetermined pressure in advance.
The control valve receives the predetermined pressure and is biased to keep the cut valve open.

Then, when the wheel cylinder side pressure is reduced by anti-skid control, the solenoid valve is switched to the communicating position based on the loosening command from the control unit to release the pressure in the pressure chamber to the suction side of the electromagnetic pump, and the control piston When the cut valve is opened by moving to the pressure chamber side and the volume of the volume chamber is increased and the reduced pressure on the wheel cylinder side is increased, the loosening command from the control unit disappears and the containment command is issued. The solenoid valve is set to the shut-off position to supply the discharge pressure liquid of the electromagnetic pump to the pressure chamber and move the control piston to the volume chamber side. When the anti-skid control is completed, the pressure in the pressure chamber is raised to a predetermined pressure in order to urge the control piston to keep the cut valve open as described above.

[Problems to be Solved by the Invention]

Therefore, if an abnormality such as a pressure leak from the pressure chamber to the electromagnetic pump or a failure of the electromagnetic pump occurs, and the pressure in the pressure chamber for urging the control piston does not reach the predetermined pressure, it drops, The cut valve is closed and the master cylinder side and the wheel cylinder side are cut off, and even if pressure is generated in the master cylinder, the pressure is not supplied to the wheel cylinder and the brake does not operate.

In order to solve this problem, it is conceivable to directly connect the master cylinder side and the wheel cylinder side when the pressure in the pressure chamber drops below a predetermined pressure.
As described above, even when the wheel cylinder side pressure is reduced by the anti-skid control, the pressure in the pressure chamber is reduced below the predetermined pressure. In this case, therefore, the master cylinder side and the wheel cylinder side are not directly connected. Need to do so.

The present invention has been made in view of the above problems, and the pressure of the pressure chamber becomes lower than a predetermined pressure only when the master cylinder side and the wheel cylinder side should be communicated with each other by opening the cut valve. Accordingly, an object of the present invention is to provide an anti-skid hydraulic pressure control device capable of directly connecting the master cylinder side and the wheel cylinder side according to the above.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a bypass valve capable of opening and closing a passage that directly connects the master cylinder side and the wheel cylinder side of the cut valve with a stepped piston, and the stepped pistons face each other. Has a large diameter end and a small diameter end, the master cylinder side pressure of the cut valve can be directly received on the large diameter end side, and the urging force according to the pressure supplied to the pressure chamber is controlled. It can be transmitted through a piston, and the wheel cylinder side pressure of the cut valve can be directly received on its small diameter end side, and it receives the biasing force of the spring to supply pressure from the master cylinder to the wheel cylinder. Accordingly, the force acting on the pressure receiving area difference between the large diameter side end and the small diameter end side, or the urging force corresponding to the predetermined pressure on the pressure chamber side transmitted from the control piston to the large diameter end side. According to any one of the above, depending on that the pressure in the pressure chamber falls below the predetermined pressure when the bypass valve is closed in a position against the biasing force of the spring and pressure is not supplied from the master cylinder to the wheel cylinder. Then, when the urging force from the control piston acting on the large diameter end side becomes smaller than the urging force of the spring,
Pressure supplied from the master cylinder to the wheel cylinder in response to the stepped piston being arranged to move from the closed position to the open position of the bypass valve and moving to the open position of the bypass valve. Has a step portion for receiving a pressure in the same direction as the urging force of the spring to offset the force acting on the pressure receiving area difference between the large diameter side end and the small diameter end side, and after receiving pressure on the step portion, Until a biasing force corresponding to the predetermined pressure is transmitted from the control piston to the large diameter end side,
The bypass valve stays in the open position.

[Work]

When the pressure chamber-electromagnetic pump system is normal, the operation is as follows.

When the brake is not activated: Pressure is not being supplied from the master cylinder to the wheel cylinder, and the stepped piston does not receive the acting force due to these pressures on the large diameter end side and the small diameter end side, but the pressure in the pressure chamber is the control piston. Since the pressure is a predetermined pressure that urges the cut valve to the open position, the stepped piston transmits its urging force to the large diameter end side from the control piston and resists the urging force of the spring acting on the small diameter end side. The bypass valve is closed. Therefore, the bypass valve does not open,
The master cylinder side and the wheel cylinder side are maintained in a state of communicating with each other through the path through the cut valve and the volume chamber.

Normal brake operation without anti-skid control:
By supplying pressure from the master cylinder to the wheel cylinder through the cut valve and the volume chamber, the stepped piston receives the acting force according to the supply pressure from the large diameter end side and the small diameter end side. It acts on the difference and continues to be urged to the position where the bypass valve is closed together with the urging force from the control piston. Therefore, the bypass valve does not open and the master cylinder side and the wheel cylinder side do not directly communicate with each other.

During anti-skid control: When the control unit issues a slack command, the solenoid valve opens and the pressure in the pressure chamber drops below a predetermined pressure, the control piston reduces the pressure supplied from the volume chamber side to the wheel cylinder. Upon receipt, the cut valve is closed and moved to increase the volume of the volume chamber. Therefore, the stepped piston cannot transmit the urging force from the control piston to the large diameter end side, but the pressure is already supplied from the master cylinder to the wheel cylinder, and the cut valve closes and the volume of the volume chamber increases, so that the pressure on the master cylinder side increases. Since the pressure on the wheel cylinder side is lower than that on the wheel cylinder side, the force acting on the large diameter end side by the master cylinder side pressure overcomes the force acting on the small diameter end side by the wheel cylinder side pressure and the spring biasing force. The stepped piston continues to be biased to the position of closing the bypass valve. Therefore, the bypass valve remains closed, the master cylinder side and the wheel cylinder side do not directly communicate with each other, and the state in which the pressure on the wheel cylinder side can be lowered and raised according to the movement of the control piston is maintained.

In this way, when the pressure chamber-electromagnetic pump system is normal, the bypass valve is kept closed, but next, an abnormality such as a pressure leak in the pressure chamber-electromagnetic pump system or an electromagnetic pump failure occurs. As for the case of occurrence, when the pressure in the pressure chamber drops below a predetermined pressure when the brake is not operating due to the occurrence of this abnormality, the bypass valve opens as follows according to this drop.

That is, when the brake is not operated, no pressure is supplied from the master cylinder to the wheel cylinder, and the stepped piston has a biasing force transmitted from the control piston on the large diameter end side and a spring biasing force on the small diameter end side. Therefore, due to the above abnormality, the pressure in the pressure chamber falls below the predetermined pressure that urges the control piston to the open position of the cut valve, and the pressure is controlled to the large diameter end side of the stepped piston. When the biasing force transmitted from the piston becomes smaller than the biasing force of the spring acting on the small diameter end side, the stepped piston accordingly moves from the closed position to the open position of the bypass valve. Then, once the bypass valve is opened by this, the master cylinder side and the wheel cylinder side are directly communicated, and the stepped piston is not only on the large diameter end side and the small diameter end side but also on the stepped portion from the master cylinder. A state in which the pressure supplied to the wheel cylinder can be received, in other words, there is substantially no difference in the pressure receiving areas facing each other, and only the biasing force of the spring is received as the acting force. Therefore, after this, even if pressure is supplied from the master cylinder to the wheel cylinder, the stepped piston is pushed to the position where the bypass valve is opened by the urging force of the spring, and the cut valve is opened between the master cylinder side and the wheel cylinder side. It is kept in a state of bypassing and communicating directly.

On the other hand, during brake operation, the pressure in the pressure chamber is lowered below a predetermined pressure by the anti-skid control, and then the pressure in the pressure chamber is controlled to the open position of the cut valve due to the occurrence of the abnormality. When the pressure cannot be increased to the predetermined pressure, the bypass valve is opened in response to the temporary release of the brake operation.

In other words, during braking, the stepped piston is already supplied with pressure from the master cylinder to the wheel cylinder, and as a result, a force greater than the biasing force of the spring that acts on the pressure receiving area difference between the large diameter end side and the small diameter end side is exerted. Since it receives it, even if the urging force from the control piston is not transmitted to the large diameter end side,
Although the bypass valve is pushed to the closed position, once the brake operation is stopped and the pressure supplied from the master cylinder to the wheel cylinder is temporarily released, the stepped piston will move to its large diameter end side and small diameter end side. The force acting on the pressure receiving area difference from the side becomes smaller than the biasing force of the spring received from the small diameter end side, and the bypass valve moves from the closed position to the open position as in the case described above. Then, once the bypass valve is opened, pressure can be directly supplied from the master cylinder to the wheel cylinder in response to the brake re-operation, and the stepped piston is bypassed by the biasing force of the spring as in the case described above. The valve is held in the open position, and the master cylinder side and the wheel cylinder side are kept in direct communication with each other, bypassing the cut valve.

〔The invention's effect〕

Thus, according to the present invention, the master cylinder and By directly communicating with the wheel cylinder by bypassing the cut valve and supplying the pressure directly from the master cylinder to the wheel cylinder, normal brake operation can be performed.
Moreover, when an abnormality occurs after the start of anti-skid control,
Since the master cylinder and the wheel cylinder do not suddenly communicate directly with each other when the brakes are operating, the pressure on the wheel cylinder side is prevented from suddenly increasing and the wheels are prevented from suddenly applying excessive brakes. You can avoid falling into a locked state that stabilizes.

〔Example〕

 An embodiment of the present invention shown in the drawings will be described below.

In the figure, the anti-skid hydraulic pressure control device of this embodiment is indicated by 1 as a whole, and hydraulic pressure is supplied from a master cylinder 2 with a vacuum booster. That is, the master cylinder 2 with a vacuum booster comprises a known vacuum booster 3 and a master cylinder 4, and the vacuum booster 3 is driven by a brake pedal 5 and the master cylinder 4 is driven by its output. The hydraulic pressure generating chamber is connected to the wheel cylinder of the front wheel via the pipe 6. The other hydraulic pressure generating chamber is connected via a pipe 7 to an input port 16 of a pressure adjusting device 8 described later, and a first output port 17 of this device 8 is connected via a pipe 9 to a rear wheel.
It is connected to the wheel cylinders 12 and 13 of 10,11 and also the second
The output port 19 is connected to the pipe 9 via the pipe 14. The control port 18 of the pressure regulator 8 is connected to the discharge port 27 of the electromagnetic pump 26 via a pipe 24 provided with a check valve 25, and branches from the pipe 24 on the control port 18 side of the check valve 25. It is connectable to the reservoir 23 via the pipe 20, the solenoid valve 21, and the pipe 22. As is well known, the reservoir 23 includes a main body 44, a slidable piston 45 with a seal ring attached to the inner hole, and a relatively weak spring 46 for urging the piston 45.
A liquid chamber and an air chamber are defined on both sides of 45. The liquid chamber communicates with the pipe 22 through the above-mentioned through hole 47, and further through a pipe 29 provided with a check valve 28, a discharge port which also serves as a suction port of the electromagnetic pump 26.
Connected to 27. The check valves 28 and 25 allow the flow from the reservoir 23 side to the electromagnetic pump 26 side and the electromagnetic pump 26 side to the control port 18 side, respectively, but prohibit the reverse. 70
Is a pressure switch provided on the control port 18 side of the check valve 25 of the pipe 24, detects the pressure of the pressure chamber 39 of the pressure adjusting device 8 described later, and when the pressure reaches a preset predetermined pressure. It switches and outputs a signal when the pressure is equal to or lower than a predetermined pressure.

The solenoid valve 21 is a two-position valve that switches in response to the demagnetization of the solenoid 21b. When the solenoid 21b is demagnetized, the urging force of the spring 21a cuts off the communication between the control port 18 side and the reservoir 23 side. A is taken, and when the solenoid 21b is excited, it takes a position B that connects the control port 18 side and the reservoir 23 side.

The electromagnetic pump 26 has a bobbin 49 in the large diameter portion of the inner hole 53 of the main body 48.
A coil 50 wound around is fixedly arranged, and a main plunger 51 made of a magnetic material is slidably fitted into a center hole of a bobbin 49. The coil 50 is excited by the current from the control unit 57, but the drawing shows the non-excitation state, and the main plunger 51 is in contact with the bottom portion 48a of the main body 48.

A stepped sub-plunger 52 is slidably fitted to the small-diameter portion of the inner hole 53 of the main body 48 with a seal ring 54 interposed therebetween, and is urged toward the bottom portion 48a by a spring 55 so that the main plunger 5
It is in contact with 1. Subplunger 5 in the normal state shown
A liquid chamber 56 having a predetermined volume (for example, 0.1 cc) is formed between the second end surface 52a and the inner wall end surface 48b of the main body 48 and communicates with the above-described discharge port 27. When the coil 50 is excited, the main plunger 51 is biased toward the discharge port 27 by the magnetic attraction force, and presses the sub-plunger 52 against the biasing force of the spring 55. The sub-plunger 52 stops when its end face 52a contacts the inner end face 48b of the main body 48, and a predetermined volume of hydraulic fluid is delivered to the pressure regulator 8 side via the check valve 25 and the pipe 24 by one stroke so far. Send in. When the coil 50 is de-energized, the biasing force of the spring 55 causes the sub-plunger 52 and the main plunger 51 to return to the positions shown in the drawing. Due to the backward stroke at this time, the working fluid is sucked from the reservoir 23 through the check valve 28 by a predetermined volume. The main plunger 51 made of a magnetic material and a part of the main body 48 form a magnetic circuit.

The electromagnetic valve 21 and the electromagnetic pump 26 described above are controlled by receiving the outputs from the output terminals 59a and 59b of the control unit 57 by receiving the solenoid 21b and the coil 50, respectively. The control unit 57 has its input terminal 58a connected to the output terminals of wheel speed detectors provided on each wheel (not shown), and performs various calculations and judgments based on the outputs of these detectors to release the brake slack signal. , Generate a brake reload signal.

Further, the output terminal of the pressure switch 70 described above is connected to the input terminal 58b, and based on the output of the pressure switch 70 generated when the pressure in the pressure chamber 39 is equal to or lower than a predetermined pressure, the electromagnetic pump
Generates 26 drive signals. However, the brake slack signal,
While the anti-skid control is being performed based on the refill signal, the output of the pressure switch 70 is invalid and the drive signal is not generated.

The output of the control unit 57 is such that when the brake slack signal is generated, the output S ₁ at the output terminal 59a connected to the solenoid 21b is high level “1” and the output S ₂ at the output terminal 59b connected to the coil 50 is low. Level "0"
Becomes Also, when the brake re-load signal is generated or the drive signal is generated, output S ₁ is a low level “0” pulse, and output S ₂ is a pulse that switches between high level “1” and low level “0” at appropriate time intervals. It becomes an output.

The pressure adjusting device 8 interposed between the master cylinder 4 and the wheel cylinders 12 and 13 has a stepped hole 30 formed inside the main body 15 and communicates with an input port 16 connected to the master cylinder 4. A stepped cut valve body 32 is slidably fitted inside the diameter hole portion 30a. The cut valve main body 32 is formed with a plurality of grooves 32a for communicating both ends of the cut valve main body 32 on the outer circumference of the large diameter portion, and a control piston 36 described later.
An annular valve body 31 made of synthetic rubber is attached to the outer periphery of the end portion facing the inner wall of the cut valve body 32 according to the movement of the cut valve body 32.
It can be attached to and detached from a valve seat 37 formed on 30c. Then, the cut valve body 32 is stretched between the inner end portion of the lid body 60 attached to the opening of the large diameter hole portion 30a and provided with the second output port 19 and the large diameter portion of the cut valve body 32. The first valve spring 40 is biased toward the valve seat 37. Such cut valve body
32 is further formed with a stepped through hole extending in the axial direction, and a valve ball is provided in the through hole on the end side where the valve body 31 is mounted.
A tapered valve seat 32b on which 35 can be attached and detached is provided. A diaphragm hole is provided at the end of the through hole facing the lid 60.
A lid member 33 provided with 34 is integrally assembled, and a second valve spring 42 having a weaker spring force than the first valve spring 40 is stretched between the lid member 33 and the valve ball 35 described above. As a result, the valve ball 35 is urged toward the valve seat 32b.

A control piston 36 having a pair of sealing members 38 mounted on the outer circumference is slidably mounted on the small diameter hole portion 30b of the stepped hole 30 which is communicated with the large diameter hole portion 30a through a communication hole 30d provided on the inner wall 30c. Between the control piston 36 and the valve seat 37 of the cut valve body 32, which is fitted, and on which the valve body 31 of the cut valve body 32 can be seated / separated, is always communicated with the wheel cylinders 12 and 13 via the first output port 17. A volume chamber 41 is defined, and a pressure chamber 39 facing the volume chamber 41 and on the opposite side of the control piston 36 and communicating with the control port 18 is defined. The control piston 36 has an end portion on the side of the volume chamber 41 that can penetrate the communication hole 30d and come into contact with the cut valve body 32, and further has a shaft-like portion 43 integrally formed at the end portion of the control piston 36. It can come into contact with the valve ball 35 inside the main body 32. In this way, the control piston corresponding to the pressure difference generated between the volume chamber 41 side and the pressure chamber 39 side.
The movement of 36 controls the seating / seating of the valve body 31 of the cut valve body 32 with respect to the valve seat 37, and the seating / separation of the valve ball 35 with respect to the valve seat 32b, depending on the movement of the control piston to the pressure chamber 39 side. , Valve body
When 31 is seated on the valve seat 37 and the valve ball 35 is seated on the valve seat 32b, the fluid communication from the inlet 16 side to the first output port 17 side is cut off.

The lid 60 attached to the opening of the large-diameter hole portion 30a of the main body 15 and extending inward thereof has a stepped hole 63 in which the large-diameter hole portion 63b opens to the cut valve main body 32 side. A stepped piston 64 is movably fitted in the hole 63. A cup seal 66 is attached to the outer periphery of the small diameter portion 64a of the stepped piston 64 that fits into the small diameter portion 63a of the stepped hole 63, with its lip portion facing the second output port 19 side. A seal ring 67 is attached to the outer circumference of the large diameter portion 64b fitted to the portion 63b. The stepped piston 64 is formed with a through hole 65 extending in the axial direction so that the inner side of the large diameter hole portion 30a in which the cut valve body 32 is disposed and the small diameter hole portion 63a side of the lid body 60 can be connected to each other. . Second output port 19 on the lid 60
The tube sheet 61 having the conical surface 62 at the tip portion protruding into the small diameter hole portion 63a press-fitted from the side is formed with a through hole 69 that connects the inside of the small diameter hole portion 63a and the second output port 19. Cage,
Due to the conical surface 62 of the tube sheet 61 and the peripheral edge of the through hole 65 at the end surface of the small diameter portion 64a of the stepped piston 64, the input port 16
-A bypass valve that can open and close the communication path between the second output ports 19 is configured. The end surface of the small diameter portion 64a of the stepped piston 64 can receive the hydraulic pressure on the wheel cylinders 12 and 13 side,
It receives the biasing force of the spring 68 arranged in the small diameter hole portion 63a. On the other hand, the end surface of the large diameter portion 64b of the stepped piston 64 is
The hydraulic pressure on the master cylinder 4 side can be received via the input port 16, and the pressure depending on the pressure in the pressure chamber 39 is supplied via the cut valve body 32 which is pressed by the control piston 36 and can abut against the end surface thereof. It is possible to receive power. In this way, the stepped piston 64 should block the communication between the input port 16 side and the second output port 19 when the force received by the end face of the large diameter portion 64b is larger than the force received by the end face of the small diameter portion 64a. The conical surface 62 of the tube sheet 61 is fitted to the peripheral edge of the opening of the through hole 65.
When the force received by the end surface of the large diameter portion 64b becomes smaller than the force received by the small diameter portion 64a, the cut valve body 32 side is moved to penetrate the input port 16 side and the second output port 19 side to communicate with each other. The opening edge of the hole 65 is separated from the conical surface 62.

When the stepped piston 64 moves to the cut valve body 32 side as described above, the portion of the large diameter portion 64b to which the seal ring 67 is attached expands from the inside of the large diameter hole portion 63b to the larger diameter hole portion 63b. The taper portion 63c is formed so as to escape.

Next, the operation of this embodiment described above will be described. The description of the brake system of the front wheels (not shown) connected to the master cylinder 4 via the pipe 6 is omitted, and the operation will be described below only for the system of the rear wheels 10 and 11 shown.

Now, it is assumed that the vehicle equipped with the hydraulic control device 1 and the master cylinder 2 with the vacuum booster is traveling at a constant speed. That is, the brake pedal 5 is not depressed, the output signals S ₁ and S ₂ of the control unit 57 are both "0", and the device 1 is in the illustrated state. At this time, the solenoid valve 21 blocks the pressure chamber 39 of the adjusting device 8 from the reservoir 23 side, and the pressure in the pressure chamber 39 is maintained at a predetermined pressure. Then, the control piston 36 receives the pressure in the pressure chamber 39 and presses the cut valve body 32 and the valve ball 35 against the spring force of the valve springs 40 and 42, so that the valve body 31 and the valve ball 35 are seated together. 37,32b
The input port 16 and the first output port 17 communicate with each other through the volume chamber 41. Further, the stepped piston 64 applies the urging force from the control piston 36 via the cut valve body 32 to the large diameter portion 64.
In response to the spring force of the spring 68, the opening peripheral edge of the through hole 65 is pressed against the conical surface 62 of the tube sheet 61 against the spring force of the spring 68, and between the input port 16 and the second output port 19. It has been cut off.

The brake pedal 5 is used to stop the vehicle in such a state.
When is strongly stepped on, the hydraulic pressure generated in the master cylinder 4 causes the pipe 7, the input port 16 of the pressure regulator 8, the volume chamber 41, the first output port.
It is supplied to the wheel cylinders 12 and 13 via 17 and the pipe 9.

The brake pressure starts to be applied to the rear wheels 10 and 11 by the hydraulic pressure supplied from the master cylinder 4 to the wheel cylinders 12 and 13, and the wheel cylinders 12 and 13 are increased according to the increase in the hydraulic pressure of the master cylinder 4.
The hydraulic pressure inside also rises. And the control unit 57
When it is determined that the brake is overloaded, the output S ₁ of the output terminal 59a becomes “1”. As a result, the solenoid 21b of the solenoid valve 21 is excited, and the solenoid valve 21 is switched from the position A that shuts off the pressure chamber 39 side of the pressure regulator 8 and the reservoir 23 side to the position B that connects them. Pressure chamber 39 of pressure regulator 8
The pressurized liquid contained in the liquid is discharged to the liquid chamber of the reservoir 23 through the pipes 20 and 22. When the pressure in the pressure chamber 39 decreases in this way, the control piston 36 is pressed by the hydraulic pressure of the master cylinder 4 supplied from the input port 16 and the pressure chamber 39.
Move to the side. With the movement of the control piston 36, the cut valve body 32 moves toward the inner wall 30c by the spring force of the first valve spring 40, the valve body 31 is seated on the valve seat 37, and then the cut valve body
The valve ball 35 in 32 is seated on the valve seat 32b by the spring force of the second valve spring 42, and the communication between the input port 16 and the volume chamber 41 is cut off.
The control piston 36 receives the hydraulic pressure on the wheel cylinders 12 and 13 side and further moves to the pressure chamber 39 side, and accordingly, the volume chamber 41
Due to the increase in the volume, the hydraulic pressure of the wheel cylinders 12 and 13 communicating with the volume chamber 41 via the first output port 17 decreases.

Stepped piston arranged between the input port 16 and the second output port 19
64 is a control piston due to the movement of the cut valve body 32 described above.
The urging force from the pressure chamber 39 side via 36 will not be received by the end surface of the large diameter portion 64b, and the end surface of the small diameter portion 64a will receive the hydraulic pressure on the wheel cylinder 12, 13 side via the pipe 14. However, the end surface of the large diameter portion 64b receives hydraulic pressure on the master cylinder 4 side via the input port 16, and the large diameter portion 64b and the small diameter portion 6 are
The acting force obtained by multiplying the difference in pressure receiving area with 4a by the hydraulic pressure is larger than the spring force of the spring 68. Therefore, the stepped piston 64 continues to be pressed by the conical surface 62 of the tube sheet 61, and the input port 16 is pressed by the pressure contact between the opening peripheral edge of the through hole 65 and the conical surface 62.
The side and the second output port 19 side are kept in the cutoff state.

When the control unit 57 determines that the brake is excessively loosened, the brake is loosened in accordance with the decrease in the hydraulic pressure on the wheel cylinders 12 and 13 side, and the output terminal 59a is output.
The output S ₁ of "1" is switched from "1" to "0", the solenoid 21b of the solenoid valve 21 is demagnetized, and the solenoid valve 21 shuts off the pressure chamber 39 side and the reservoir 23 side by the spring force of the spring 21a. Is switched to. At this time, by stopping the liquid discharge from the pressure chamber 39 to the liquid chamber of the reservoir 23, the movement of the control piston 36 is stopped, the volume of the volume chamber 41 does not change, and the hydraulic pressure on the wheel cylinders 12 and 13 side is stopped. Is kept constant. After that, the output S ₂ of the output terminal 59b of the control unit 57 becomes a pulse output that switches between "1" and "0" at an appropriate time interval, and this output is guided to the coil 50 of the electromagnetic pump 26.

Then, when the output S ₂ becomes “1”, the electromagnetic pump 26 turns the coil 50
Is excited. The magnetic attraction force moves the main plunger 51 and the sub-plunger 52 against the spring force of the spring 55, and the liquid chamber 56
The liquid inside is sent into the pressure chamber 39 of the pressure regulator 8 via the check valve 25. The sub-plunger 52 is stopped by coming into contact with the inner end wall surface 48b of the main body 48, and thereafter, the output signal output S ₁ becomes “0”.
However, the liquid of a fixed volume in the liquid chamber 56 is sent into the pressure chamber 39 of the pressure regulating device 8 by one stroke during this forward movement, and the control piston 36 is moved by the amount of this liquid volume. Moving to the chamber 41 side, the volume of the volume chamber 41 decreases. Then, the hydraulic pressure on the wheel cylinders 12 and 13 side increases due to this volume decrease.

When the output S ₂ becomes "0", the coil 50 is demagnetized, so that the main plunger 51 and the sub plunger 52 are returned by the spring force of the spring 55. At this time, the check valve 28 is used. The liquid is sucked into the liquid chamber 56 from the reservoir 23. Plunger
Since the liquid is not supplied to the pressure chamber 39 of the pressure regulator 8 during the backward movement of the pressure adjusting device 51, 52, the hydraulic pressure on the wheel cylinder 12, 13 side becomes constant.

When the output S ₂ becomes “1” again and the coil 50 is excited, as described above, the forward movement of the main plunger 51 and the sub-plunger 52 causes the liquid of a constant volume in the liquid chamber 56 to move to the pressure chamber 39 of the pressure regulator 8. And the control piston 36 moves by the amount of the liquid,
The volume of 41 decreases, and the hydraulic pressure on the wheel cylinder 12, 13 side increases.

In this way, while the pulsed output S ₂ is supplied from the control unit 57 to the coil 50 of the electromagnetic pump 26, the electromagnetic pump 26 discharges the liquid to the pressure chamber 39 side and the reservoir 23.
Control piston by repeating liquid suction from the side
36 moves while decreasing the volume of the volume chamber 41, and accordingly, the hydraulic pressure on the wheel cylinders 12 and 13 side gradually increases. Then, when the shaft-shaped portion 43 provided at the end of the control piston 36 pushes the valve ball 35 to separate it from the valve seat 32b in response to the movement of the control piston 36, the large-diameter hole portion 30a is passed through the input port 16. The hydraulic pressure of the master cylinder 4 supplied into the wheel cylinders 12 and 13 through the throttle valve 34 of the lid member 33, the cut valve main body 32, the volume chamber 41 and the first output port 17, As a result, the hydraulic pressure on the wheel cylinders 12 and 13 side is further increased.

In this way, when the brakes of the rear wheels 10 and 11 are applied and the control unit 57 determines that the braking is excessive, the output S ₁ of the output terminal 59a becomes "1". At this time, the pulse output of the output S _{2 at} the output terminal 59b has already disappeared. When the output S ₁ becomes "1", the solenoid 21b of the solenoid valve 21 is excited, and the solenoid valve 21 moves to the pressure chamber 39 side and the reservoir 23 side.
The position is switched to the position B for communicating with the side. In this way, the pressure liquid in the pressure chamber 39 is again discharged to the liquid chamber of the reservoir 23, and when the pressure in the pressure chamber 39 decreases, the control piston 36 is pressed by the hydraulic pressure on the wheel cylinders 12 and 13 side, and the pressure chamber 39 side. To the wheel cylinder.
The hydraulic pressure on the 12 and 13 side decreases.

Thereafter, the outputs S ₁ , S of the control unit 57 are output in the same manner as described above.
_{Based on 2} , hold and raise hydraulic pressure on wheel cylinders 12, 13 side,
By repeating the operation of lowering, the anti-skid control is continued, and the vehicle is decelerated and stopped without locking the rear wheels 10 and 11.

When the above-mentioned anti-skid control is completed, the pressure regulator 8
If the pressure in the pressure chamber 39 is lower than the predetermined pressure for urging the control piston 36 to keep the valve body 31 and the valve ball 35 separated from the valve seats 37, 32b, Upon receiving the output of the switch 70, the control unit 57 generates a drive signal for the electromagnetic pump 26, and the output S ₂ at the output terminal 59b becomes a pulse output. As a result, the electromagnetic pump 26 is driven in the same manner as when the brake is reloaded as described above, and the discharge pressure liquid is discharged from the pressure chamber.
Supplied to 39.

Then, the control piston 36 connects the valve body 31, the valve ball 35 to each valve seat 37,
When the pressure of the pressure chamber 39 reaches a predetermined pressure by returning to the position shown in the drawing in which the cut valve body 32 is separated from 32b and the cut valve body 32 is brought into contact with the end surface of the large diameter portion 64b of the stepped piston 64, the pressure switch 70 And the output disappears,
The output S ₂ of the control unit 57 becomes “0”, and the liquid discharge of the electromagnetic pump 26 ends.

When the brake pedal 5 is released, the wheel cylinders 12, 1
The hydraulic pressure supplied to 3 is released to the master cylinder 4 side through the first output port 17, the volume chamber 41, and the input port 16, and the rear wheel 1
The brake applied to 0 and 11 is released.

Hereinafter, the pressure in the pressure chamber 39 of the pressure regulator 8 is set to a predetermined pressure, and the control piston 36 is urged against the spring force of the valve springs 40 and 42 and the hydraulic pressure acting from the volume chamber 41 side. Cut valve body 32
The normal case in which the valve can be kept in the open position has been described.Next, if the pressure in the pressure chamber 39 does not reach the predetermined pressure due to damage to the piping connected to the control port 18, failure of the electromagnetic pump 26, or the like. The case of disappearing will be described.

When the brake pedal 5 is not stepped on and the brake is not operated, pressure leakage occurs and the pressure in the pressure chamber 39 drops below a predetermined pressure, and the cut valve body 32 is opened via the control piston 36. If the force urging the valve from the pressure chamber 39 side is smaller than that of the valve springs 40 and 42, the cut valve body 32
Presses the control piston 36 and moves toward the valve seat 37.
Then, the valve body 31 is seated on the valve seat 37, and the valve ball 35 is placed in the second position.
By pressing the shaft-like portion 43 of the control piston 36 by the spring force of the valve spring 42 and seating it on the valve seat 32b, the communication between the input port 16 and the first output port 17 is cut off.

However, in this case, the input port 16 and the second output port 19
The stepped piston 64 provided between and has a biasing force transmitted from the control piston 36 via the cut valve body 32 that comes into contact with the end surface of the large diameter portion 64b, that is, the force pressed to the tube seat 61 side. I will not receive it. Since the brake is not operated, the end surface of the large diameter portion 64b and the end surface of the small diameter portion 64a of the stepped piston 64 are the master cylinder 4, the wheel cylinders 12 and 1.
Since the hydraulic pressure of 3 is not received, the stepped piston 64 eventually becomes
It is pressed by the spring force of the spring 68 acting on the end surface of the small diameter portion 64a and moved to the cut valve body 32 side. In response to this movement, the opening peripheral edge of the through hole 65 on the small diameter portion 64a side is separated from the conical surface 62 of the tube sheet 61, and the portion of the large diameter portion 64a where the seal ring 67 is mounted is tapered from the inside of the large diameter hole portion 63b. Exit to 63c. Thus, the input port 16 and the second output port 1
9 communicates with each other through the through hole 65 of the stepped piston 64, the gap between the stepped piston 64 and the tube sheet 61, the small diameter hole portion 63a, and the passage 69.

Therefore, even if the input port 16 and the first output port 17 are cut off, when the brake pedal 5 is stepped on to operate the brake, the hydraulic pressure generated in the master cylinder 4 becomes Wheel cylinder 1 through 2 output ports 19 and piping 14
It is supplied to 2, 13 and the rear wheels 10, 11 are braked.

When hydraulic pressure is supplied from the master cylinder 4 to the wheel cylinders 12 and 13, the small diameter portion 64a end surface and the large diameter portion 64b end surface of the stepped piston 64 respectively receive the hydraulic pressure, but the large diameter portion 64b The part where the seal ring 67 is attached is the tapered part 63c
As a result, the hydraulic pressure also acts on the stepped portion that connects the small diameter portion 64a and the large diameter portion 64b, and the stepped piston 64 applies the same hydraulic pressure to each of the opposing pressure receiving surfaces of substantially the same area. Will receive. Therefore, a failure such as a pressure leak on the pressure chamber 39 side is repaired, a predetermined pressure is supplied into the pressure chamber 39, and the control piston 36 is provided to the end surface of the large diameter portion 64b of the stepped piston 64 via the cut valve body 32. Until the urging force from is applied, the stepped piston 64
Does not move to the tube sheet 61 side, and the communication between the input port 16 and the second output port 19 is maintained.

When the brake pedal is not depressed and the brake is not operated, the pressure in the pressure chamber 39 is a predetermined pressure, and the hydraulic pressure of the master cylinder 4 is changed according to the depression of the brake pedal 5 into the input port 16, the volume chamber 41, and the volume chamber 41. It is assumed that the pressure is supplied to the wheel cylinders 12 and 13 through the first output port 17 to start the brake operation, and the pressure in the pressure chamber 39 is reduced by the anti-skid control so as to loosen the brake of the rear wheels 10 and 11 as described above.
Then, after that, the pressure in the pressure chamber 39 cannot be increased due to the failure of the electromagnetic pump 26, and the decreased hydraulic pressure on the wheel cylinder 12, 13 side cannot be increased according to the movement of the control piston 36. In this case, by pressing the brake pedal 5 again, hydraulic pressure can be supplied through the second output port 19.

That is, since the brake pedal 5 is already depressed and the hydraulic pressure acting on each of the end surface of the small diameter portion 64a and the end surface of the large diameter portion 64b of the stepped piston 64 is released by once stopping the depression of the brake pedal 5. As in the case described above, the stepped piston 64 is pressed by the spring force of the spring 68 acting on the end surface of the small diameter portion 64a, and the valve body 31 faces the cut valve body 32 side where it is seated on the valve seat 37. Be moved. Then, in response to this, the peripheral edge of the opening of the through hole 65 is the conical surface 62
The input port 16 and the second output port 19 communicate with each other. Therefore, the hydraulic pressure of the master cylinder 4 generated by the further depression of the brake pedal 5 is directly supplied to the wheel cylinders 12 and 13, and the hydraulic force on the wheel cylinders 12 and 13 side is increased to increase the rear wheel 1.
The braking force acting on 0 and 11 increases.

When the pressure leak or the malfunction of the electromagnetic pump 26 is repaired and a predetermined pressure is supplied into the pressure chamber 39, the control piston 36 receives the pressure and presses the cut valve body 32 and the stepped piston 64, The cut valve body 32 separates from the valve seat 37, and the input port 16 and the first output port 17 communicate with each other. Then, the portion of the large diameter portion 64b of the stepped piston 64 to which the seal ring 67 is attached fits into the large diameter hole portion 63b, the opening peripheral edge of the through hole 65 on the small diameter portion 64a side is pressed against the conical surface 62, and input. The opening 16 and the second output opening 19 are disconnected from each other, and the state returns to the illustrated state. The liquid that has entered the space between the outer circumference of the small diameter portion 64a of the stepped piston 64 and the inner circumference of the large diameter portion 63b of the stepped hole 63 is urged by the stepped piston 64 from the control piston 36 as described above. Received tube sheet 61
Cup seal 6 attached to the small diameter part 64a when moving to the side
By deforming the lip part of 6, the outer circumference of the small diameter portion 64a and the small diameter hole portion 63a
It is discharged to the side of the second output port 19 through the gap between and.

As described above, in the present embodiment, the large diameter portion 64b
The end surface receives the hydraulic pressure of the master cylinder 4, and the pressure chamber 39
Controls urging force according to pressure of piston 36, cut valve body 3
The piston 64, which can be received via the second small diameter portion 64a and receives the hydraulic pressure on the wheel cylinders 12 and 13 side via the second output port 19 and the spring force of the spring 68, is attached to the end surface of the small diameter portion 64a.
A bypass valve that is movably disposed in 63 and is opened and closed by the movement of the stepped piston 64 is provided in a passage that connects the input port 16 and the second output port 19 with the peripheral edge of the through hole 65 of the stepped piston 64. By providing the conical surface 62 of the tube sheet 61 and providing it, the master cylinder 4 to the wheel cylinders 12, 1
When the pressure in the pressure chamber 39 becomes lower than the predetermined pressure that urges the cut valve body 32 to the open position when the brake is not operated and the hydraulic pressure is not supplied to 3, the small diameter portion 64a of the stepped piston 64 is
The spring force of the spring 68 acting on the end face overcomes the urging force acting on the end face of the large diameter portion 64b via the cut valve body 32 and the control piston 36, and the step piston 64 moves to open the peripheral edge of the through hole 65. Is separated from the conical surface 62, and the input port 16 and the second output port 19 communicate with each other.

Therefore, due to pressure leakage or failure of the electromagnetic pump 26, the pressure chamber 39
From the master cylinder 4 through the input port 16, the volume chamber 41, and the first output port 17 due to the valve body 31 and the valve ball 35 sitting on the valve seats 37 and 32b. Wheel cylinder
Even if the liquid cannot be supplied to 12 and 13, the second from the input port 16
Since the liquid can be supplied to the wheel cylinders 12 and 13 through the output port 19, it is possible to perform a normal brake operation according to the hydraulic pressure generated in the master cylinder 4.

And wheel cylinder 1 by anti-skid control
When the pressure in the pressure chamber 39 is lowered below a predetermined pressure in order to reduce the 2,13 side hydraulic pressure by the movement of the control piston 36, the hydraulic pressure on the master cylinder 4 side acting on the end surface of the large diameter portion 64 is set. The corresponding pressing force overcomes the acting force corresponding to the hydraulic pressure on the wheel cylinders 12 and 13 side acting on the end surface of the small diameter portion 64a and the spring force of the spring 68, so that the peripheral edge of the through hole 65 of the stepped piston 64 has a conical surface 62. Since the master cylinder 4 side and the wheel cylinders 12 and 13 side are not brought into direct contact with each other because they are pressed against each other.

Further, since the stepped piston 64 is also used as the valve element of the bypass valve for opening and closing the passage that connects the master cylinder 4 side and the wheel cylinders 12 and 13 side through the second output port 19, the stepped piston 64 is also used. The master cylinder 4 side and the wheel cylinders 12 and 13 are immediately released according to the movement of the attached piston 64 to the pressure chamber 39 side.
The side can be directly communicated, and the number of parts of the pressure adjusting device 8 can be reduced to perform the above-described operation.

Although the embodiment shown in the drawings has been described above, the present invention is not limited to this, and for example, the stepped piston 64 and the cut valve body 32 are arranged coaxially, and depending on the pressure of the pressure chamber 39. Control piston 36 and cut valve body 32
Instead of transmitting to the end surface of the large-diameter portion 64b of the stepped piston 64 via the stepped piston, the stepped piston is installed in parallel with the cut valve, and the transmission member is interposed between the stepped piston and the control piston. Alternatively, or only via the control piston, the biasing force according to the pressure in the pressure chamber may be transmitted to the end surface of the large diameter portion of the stepped piston. Further, instead of connecting the end surface side of the small diameter portion 63 of the stepped piston 64 and the wheel cylinders 12 and 13 side via the second output port 19 and the pipe 14, a passage communicating with the first output port 17 is provided. Body 15 of pressure regulator 8
You may make it connect to it through the passage provided in the.
In addition, a valve mechanism having a valve body provided separately from the stepped piston may be arranged in a passage that directly connects the master cylinder 4 side and the wheel cylinders 12 and 13 side by bypassing the cut valve. Good.

[Brief description of drawings]

The drawing shows a cross-sectional view of an embodiment of the present invention together with a piping system of a brake device. 1 …… Anti-skid hydraulic pressure control device 16 …… input port, 17 …… first output port 19 …… second output port, 21 …… solenoid valve 26 …… solenoid pump, 32 …… cut valve body 36… Control piston, 39 Pressure chamber 41 Volume chamber 62 Conical surface 64 Stepped piston

Claims (1)

[Claims] 1. A cut valve disposed between a master cylinder and a wheel cylinder, a volume chamber formed on the wheel cylinder side of the cut valve, and a movable valve that is movable to open and close the cut valve. A control piston capable of increasing or decreasing the volume of the volume chamber, and a control piston formed on the side opposite to the volume chamber of the control piston for opening the cut valve against the pressure on the volume chamber side. A pressure chamber into which the urging pressure is introduced, an electromagnetic pump that is provided so as to be able to supply the discharge pressure to the pressure chamber and that is driven based on a loading command from the control unit that determines the rotation state of the wheels, and the control unit from the control unit. A solenoid valve that switches from a cutoff position to a communication position based on a slack command and connects the pressure chamber to the suction side of the electromagnetic pump, and when not operating, sets the solenoid valve to the cutoff position. In the anti-skid hydraulic pressure control device configured to urge the control piston to the valve opening position of the cut valve by the predetermined pressure supplied from the electromagnetic pump to the pressure chamber, the master of the cut valve is used. A bypass valve capable of opening and closing a passage that directly connects the cylinder side and the wheel cylinder side with a stepped piston is provided, and the stepped piston has a large diameter end and a small diameter end facing each other, and the large diameter end side thereof The pressure on the master cylinder side of the cut valve can be directly received, and the urging force corresponding to the pressure supplied to the pressure chamber can be transmitted via the control piston. The wheel cylinder side pressure of the valve can be directly received, and the large diameter side end and small diameter side are received in response to the pressure supply from the master cylinder to the wheel cylinder by receiving the biasing force of the spring. The biasing force of the spring by either the force acting on the pressure receiving area difference with the side or the biasing force transmitted from the control piston to the large diameter end side according to the predetermined pressure on the pressure chamber side. Staying in the position where the bypass valve is closed against the action of the master cylinder and the pressure in the pressure chamber when the pressure is not supplied from the master cylinder to the wheel cylinder is lowered below the predetermined pressure. When the biasing force from the control piston becomes smaller than the biasing force of the spring, the bypass piston is arranged to move from the closed position to the open position, and the stepped piston opens the bypass valve. As it moves to the position, the pressure supplied from the master cylinder to the wheel cylinder is received in the same direction as the urging force of the spring, and the pressure receiving surfaces of the large diameter side end and the small diameter end side. Having a step portion for canceling the force acting on the product difference, after receiving pressure on the step portion, until a biasing force corresponding to the predetermined pressure is transmitted from the control piston to the large diameter end side, A hydraulic control device for anti-skid, which is adapted to remain in the position where the bypass valve is opened.